For almost a century, astronomers have understood that the universe is in a state of expansion. Since the 1990s, they have realized that four billion years ago, the rate of expansion was accelerating. As this progresses, and the galaxy clusters and filaments of the universe move farther away, scientists theorize that the average temperature of the universe will gradually decrease.
But according to new research led by Ohio State University’s Cosmology and Astroparticle Physics (CCAP), it looks like the universe is really warming up over time. After examining the thermal history of the universe over the last 10 billion years, the team concluded that the average temperature of cosmic gas has increased more than 10 times and reached about 2.2 million K (~ 2.2 ° C; 4 million-F) today.
The study, which describes their findings, was recently published as “Cosmic Thermal History Examined by Zeldovich Effect Tomography”. Astrophysical Journal. The study was led by CCAP research partner Yi-Kuan Chiang, and included members of the Universe Physics and Mathematics (Kavali IPMU), Johns Hopkins University, and Max-Planck-Institute. Astrophysics.
For their study, the team examined thermal data on the large-scale structure (LSS) of the universe. This refers to patterns of galaxies and objects on the largest scale in the universe, the result of the gravitational collapse of dark matter and gas. As Dr. Chung Chiang explained in an Ohio State News publication:
“Our new criterion provides direct confirmation of the half-work by Jim Pebbles – the 2019 Nobel laureate in physics – who introduced the theory of how large-scale formations form in the universe. As the universe evolves, gravity pulls dark matter and gas into space into galaxies and clusters of galaxies. The cramps are violent – so violent that more and more gas shocks and heats up. “
To measure thermal change over the past 10 billion years, Chiang and his colleagues combined data from ESA Planck Infrared Astronomical Satellite And Sloan Digital Sky Survey (SDSS). While Planck The first European mission to measure the temperature of the Cosmic Microwave Background (CMB), the SDSS is a giant multi-spectral survey that created the most detailed 3D maps of the universe.
Out of these data sets, the team correlated eight out of eight PlanckSky intensity maps with two million spectroscopic redshift references from SDSS. Based on combing redshift measurements (which are routinely used to determine how fast our objects are moving past us) and temperature estimates, the team compared the temperatures of more distant gas clouds (later in time) with those closest to Earth.
Of these, the research team was able to confirm that the average temperature of the gases in the early universe (4 billion d) lr after the Big Bang) was lower than at present. This is apparently due to the gravitational collapse of the cosmic structure over time, a trend that will continue and intensify as the universe expands.
As Chiang summarizes, the universe is warming due to the natural process of galaxy and structure formation, and here is not related to the change in temperature on Earth:
“As the universe evolves, gravity draws dark matter and gas into space simultaneously into galaxies and clusters of galaxies. The cramps are violent – so violent that more and more gas shocks and heats up … This phenomenon is happening on very different scales. They are not all connected. “
In the past, many astronomers have argued that cooling will continue as the universe expands, resulting in a “big chill” (or “big freeze”). In contrast, Chiang and his colleagues showed that scientists could “evolve” the structure of the universe by “checking the temperature” of the universe.
These findings may also have implications for theories that accept “cosmic cooling” as a precedent. On the one hand, it has been suggested that the possible resolution of the Fermi paradox is that the Intelligence of the outside world (ETI) is inactive and waiting for the universe to improve (Estimation Hypothesis).
As part of the thermodynamics of computing (Landauer’s theory), the argument goes that as the universe cools, advanced species will be able to get much further out of their megastructures. Also, if the cosmos gets hotter with time, does that mean that the emergence of life will decrease over time due to increased cosmic radiation?
Assuming there is no system to maintain a certain thermal balance, does this mean that the universe will not end in a “Big Chill”, but a “Big Blaze”? As Robert Frost famously wrote, “Some say the world will end in fire, others say in ice.” Only time will tell which of these will prove to be true, and what effect it may have on his future life.
Further reading: Ohio State News, Astrophysical Journal
